The class of polymers of carbon monoxide and olefin(s) has been known for some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators, e.g., peroxy compounds. U.S. Pat. No. 1,081,304 produced similar polymers of somewhat higher carbon monoxide content in the presence of alkylphosphine complexes of palladium as catalyst. Nozaki extended the reaction to produce linear alternating polymers in the presence of arylphosphine complexes of palladium moieties and certain inert solvents. See, for example, U.S. Pat. No. 3,694,412.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon has become of greater interest in part because of the greater availability of the polymers. More recent processes for the production of such polymers, now becoming known as polyketones or polyketone polymers, are illustrated by a number of published European Patent Applications including Nos. 121,965, 181,014, 213,671 and 257,663. The process, now considered broadly conventional, generally involves the use of a catalyst composition formed from a compound of a Group VIII metal selected from palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa below about 6, preferably below 2, and a bidentate ligand of phosphorus, arsenic or antimony.
The resulting polymers are relatively high molecular weight materials having established utility as premium thermoplastics in the production of shaped articles by methods conventional for the processing of thermoplastics. Although the polyketone polymers are relatively stable, they do undergo to some degree the degradation upon exposure to elevated temperatures characteristic of most if not all organic polymers.
Russell et al, U.S. Pat. No. 3,929,727 and U.S. Pat. No. 4,024,104, teach the use of certain hindered phenolic benzophenones and benzotriazines as thermal stabilizers of certain polymers of carbon monoxide and ethylene with the optional presence of third mononers. Although the scope of the disclosure of polymers by Russell et al is rather broad including linear alternating polymers, the scope of the polymers tested is rather narrow and the Russell et al teachings do not appear to be directed to linear alternating polymers. A copending U.S. patent application, Ser. No. 382,512, filed July 20, 1989 now abandoned describes and claims the use of, inter alia, certain alkylated hydroquinones as thermal stabilizers for polyketone polymers. It would be of advantage, however, to provide additional thermal stabilizers for linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon.